giacomoV giacomoV - 1 month ago 18
R Question

dplyr - summarise weighted data

Is there a possibility to use weights with dplyr

summarise


function ?

Let us imagine I want to calculate a weighted table

dta = structure(list(PHHWT14 = c(530, 457, 416, 497, 395, 480, 383,
420, 499, 424, 504, 497, 449, 406, 492, 470, 418, 407, 403, 362,
393, 368, 423, 448, 511, 511, 423, 470, 453, 429, 439, 425, 431,
443, 480, 452, 472, 406, 460, 436, 574, 456, 399, 476, 423, 501,
399, 459, 396, 409, 423, 399, 383, 433, 436, 413, 403, 414, 410,
337, 472, 448, 487, 442, 475, 410, 478, 483, 374, 414, 514, 422,
409, 455, 464, 362, 461, 356, 464, 456, 494, 348, 464, 432, 398,
426, 418, 429, 516, 363, 455, 413, 388, 508, 381, 439, 330, 385,
393, 454), SEX = structure(c(2L, 1L, 2L, 2L, 1L, 2L, 2L, 1L,
2L, 2L, 2L, 1L, 2L, 1L, 2L, 2L, 2L, 1L, 2L, 2L, 2L, 2L, 2L, 2L,
2L, 2L, 1L, 2L, 2L, 2L, 2L, 2L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
2L, 2L, 2L, 2L, 1L, 2L, 2L, 2L, 1L, 2L, 2L, 1L, 2L, 2L, 2L, 1L,
2L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 1L, 2L, 2L, 1L, 2L, 2L, 1L,
2L, 2L, 2L, 1L, 2L, 2L, 2L, 2L, 2L, 1L, 2L, 2L, 1L, 2L, 1L, 2L,
2L, 2L, 2L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L), .Label = c("Female", "Male"), class = "factor")), row.names = c(NA, 100L), class = "data.frame", .Names = c("PHHWT14", "SEX"))


Using xtabs

xtabs(PHHWT14 ~ SEX, dta)


I will get

SEX
Female Male
10115 33490


Is there a way to use summarise with weights ?

dta %>%
group_by(SEX) %>%
summarise(n())


Any ideas ?

Answer

You can also use summarise_each. For your example that is the same as the summarise version, but if you have additional columns you would like to summarise, it is very helpful.

dta %>% 
  group_by(SEX) %>% 
  summarise_each(funs(sum))
## Source: local data frame [2 x 2]
##
##     SEX PHHWT14
## 1 Female   10115
## 2   Male   33490
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